Catherine Anne Grant Sadleir CNZM (born 14 August 1964) is a New Zealand sports executive and former synchronized swimmer.

[2] Sadleir first participated in synchronised swimming when she was living in Canada, aged 8, and represented the country in the sport.

[2] She later competed for New Zealand at the 1984 Summer Olympics in Los Angeles with her sister Lynette Sadleir.

[1] At the 1986 Commonwealth Games in Edinburgh, Sadleir won the bronze medal in the women's solo.

[6] In the 2024 King's Birthday Honours, Sadleir was appointed a Companion of the New Zealand Order of Merit, for services to sports governance and women.